The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingCustomize parameters
Customizing function with intelligent
tester (reference)
Hint:
The following item can be customized.
Notice:
When the customer requests a change in a
function, first make sure that the function can be
customized.
Make a note of the current settings before
customizing.
When tr ...
Removal
Hint:
Use the same procedures for the rh side and lh side.
The procedures listed below are for the lh side.
When removing the moulding, heat the vehicle body and
moulding using a heat light.
Standard heating temperature
Notice:
Do not heat the vehicle body and moulding
excessively.
...
Disassembly
Remove magnetic switch assembly
Remove the nut and disconnect the lead wire from
the magnetic switch.
Remove the 2 screws holding the magnetic switch
to the starter drive housing.
Remove the magnetic switch.
Remove the return spring and plunger from the
starter drive hou ...